Re: Chokes

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi Jason,

On 22 Oct 2001, at 8:07, Tesla list wrote:

> Original poster: "Jason by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<jasonp-at-btinternet-dot-com>
> 
> Hi all,
> 
> I know that this string won't die, but I feel that I have a point that I
> need to raise with the choke-haters :). What if you match the choke to a
> resistor, so you reach a critical damping point to stop the choke inputting
> pulses into the transformer or resonating??? I was talking to a friend about
> the filter for his big coil, and he uses chokes for it. I am currently
> running some simulations to see what kind of resistance I need.... I think
> however that it could work very well for a coil that is too big to use a
> terry style filter. I am always going to use a filter, because there is some
> sensitive equipment on my AC line that I would like to keep whole....

If you dampen the choke to that extent, you may as well use 
capacitors instead. The whole point of building LC filters for more 
traditional uses was to keep the insertion loss down in the passband 
(you naturally lose a considerable amount in RC or LR filters). 
However, the passband frequency in this case is vastly lower than the 
ones you are trying to protect your transformer against (as good as 
DC in fact) so the rationale for using inductors goes out the window. 

Regards,
malcolm